1,433 research outputs found
Electrical conduction of silicon oxide containing silicon quantum dots
Current-voltage measurements have been made at room temperature on a Si-rich
silicon oxide film deposited via Electron-Cyclotron Resonance Plasma Enhanced
Chemical Vapor Deposition (ECR-PECVD) and annealed at 750 - 1000C. The
thickness of oxide between Si quantum dots embedded in the film increases with
the increase of annealing temperature. This leads to the decrease of current
density as the annealing temperature is increased. Assuming the Fowler-Nordheim
tunneling mechanism in large electric fields, we obtain an effective barrier
height of 0.7 0.1 eV for an electron tunnelling
through an oxide layer between Si quantum dots. The Frenkel-Poole effect can
also be used to adequately explain the electrical conduction of the film under
the influence of large electric fields. We suggest that at room temperature Si
quantum dots can be regarded as traps that capture and emit electrons by means
of tunneling.Comment: 14 pages, 5 figures, submitted to J. Phys. Conden. Mat
Recommended from our members
Why does early childhood deprivation increase the risk for depression and anxiety in adulthood? A developmental cascade model
Abstract Background: Using data from the English & Romanian Adoptees (ERA) study we recently reported that early time-lmited exposure to severe institutional deprivation is
associated with early onset and persistent neurodevelopmental problems and later
onset emotional problems. Here we examine possible reasons for the late
emergence of emotional problems in this cohort. Our main focus is on testing a
developmental cascade mediated via the functional impact of early-appearing
neurodevelopmental problems on late adolescent functioning. We also explore a
second putative pathway via sensitization to stress. Methods: The ERA study includes 165 Romanian individuals who spent their early lives in grossly depriving institutions and were subsequently adopted into UK
families, along with 52 UK adoptees with no history of deprivation. Age six years
symptoms of neurodevelopmental problems and age 15 anxiety/depression
symptoms were assessed via parental reports. Young adult symptoms of depression
and anxiety were assessed by both parent and self-reports; young adults also
completed measures of stress reactivity , exposure to adverse life events and
functioning in work and interpersonal relationships. Results: The path between early institutional deprivation and adult emotional problems was mediated via the impact of early neurodevelopmental problems on
unemployment and poor friendship functioning during the transition to adulthood.
The findings with regard to early deprivation, later life stress reactivity and emotional
problems were inconclusive.
Conclusions: Our analysis suggests that the risk for adult depression and anxiety following extreme institutional deprivation is explained through the effects of early neurodevelopmental problems on later social and vocational functioning. Future research should more fully examine the role of stress susceptibility in this model
Electron and hole mobility reduction and Hall factor in phosphorus-compensated p-type silicon
The conductivity mobility for majority carrier holes in compensated p-type silicon is determined by combined measurement of the resistivity and the net doping, the latter via electrochemical capacitance-voltage measurements. The minority electron mobility was also measured with a technique based on measurements of surface-limited effective carrier lifetimes. While both minority and majority carrier mobilities are found to be significantly reduced by compensation, the impact is greater on the minority electron mobility. The Hall factor, which relates the Hall mobility to the conductivity mobility, has also been determined using the Hall method combined with the capacitance-voltage measurements. Our results indicate a similar Hall factor in both compensated and noncompensated samples.This work was supported by the Australian Research
Council ARC and by the DAAD/Go8 researcher exchange
funding scheme
Preparing to work: dramaturgy, cynicism and normative ‘remote’ control in the socialization of graduate recruits in management consulting
online) This paper examines the socialization of graduate recruits into a knowledge intensive labour
process and organizational culture. Theoretically the paper draws upon the idea of ‘preparing
for work’ to position this early socialization as a crucial moment in the production of
subjectivities suited (and booted) for the labour process of management consulting. Empirically
the paper reports on a two-day induction session for new graduate recruits joining a global
management consultancy and their responses to this training. Particular attention is given to
the use of role-play and a dramaturgical workshop used in part of the training process. The paper
argues that the utilization of dramaturgy in training is consistent with the overall approach to
control developed in the firm in response to the fact that the labour process of consulting is
often conducted on client sites, away from any direct supervisory gaze. As such, the consultants
were subjected to a form of cultural control that was designed to function independently of
direct supervision. This control did not operate directly upon the new employees professed
values, however, but at one step removed so that a ‘cynical distance’ from the content of the
organization’s culture was accepted so long as a professional ‘ethic of behaviour’ was
established. By focusing on an ‘ethic of behaviour’ these young professionals were encouraged
to internalize a self-control akin to that of an actor, rather than internalizing the corporate values
entirely
The Temporality of Power and the Power of Temporality:Imaginary Future Selves in Professional Services Firms
The golden circle: A way of arguing and acting about technology in the London ambulance service
This paper analyses the way in which the London Ambulance Service recovered from the events of October 1992, when it implemented a computer-aided despatch system (LASCAD) that remained in service for less than two weeks. It examines the enactment of a programme of long-term organizational change, focusing on the implementation of an alternative computer system in 1996. The analysis in this paper is informed by actor-network theory, both by an early statement of this approach developed by Callon in the sociology of translation, and also by concepts and ideas from Latour’s more recent restatement of his own position. The paper examines how alternative interests emerged and were stabilized over time, in a way of arguing and acting among key players in the change programme, christened the Golden Circle. The story traces four years in the history of the London Ambulance Service, from the aftermath of October 1992 through the birth of the Golden Circle to the achievement of National Health Service (NHS) trust status. LASCAD was the beginning of the story, this is the middle, an end lies in the future, when the remaining elements of the change programme are enacted beyond the Golden Circle
On the making and taking of professionalism in the further education workplace
This paper examines the changing nature of professional practice in English further education. At a time when neo-liberal reform has significantly impacted on this under-researched and over-market-tested sector, little is known about who its practitioners are and how they construct meaning in their work. Sociological interest in the field has tended to focus on further education practitioners as either the subjects of market and managerial reform or as creative agents operating within the contradictions of audit and inspection cultures. In challenging such dualism, which is reflective of wider sociological thinking, the paper examines the ways in which agency and structure combine to produce a more transformative conception of the further education professional. The approach contrasts with a prevailing policy discourse that seeks to re-professionalise and modernise further education practice without interrogating either the terms of its professionalism or the neo-liberal practices in which it resides
Forensic analysis of the microbiome of phones and shoes
BACKGROUND: Microbial interaction between human-associated objects and the environments we inhabit may have forensic implications, and the extent to which microbes are shared between individuals inhabiting the same space may be relevant to human health and disease transmission. In this study, two participants sampled the front and back of their cell phones, four different locations on the soles of their shoes, and the floor beneath them every waking hour over a 2-day period. A further 89 participants took individual samples of their shoes and phones at three different scientific conferences. RESULTS: Samples taken from different surface types maintained significantly different microbial community structures. The impact of the floor microbial community on that of the shoe environments was strong and immediate, as evidenced by Procrustes analysis of shoe replicates and significant correlation between shoe and floor samples taken at the same time point. Supervised learning was highly effective at determining which participant had taken a given shoe or phone sample, and a Bayesian method was able to determine which participant had taken each shoe sample based entirely on its similarity to the floor samples. Both shoe and phone samples taken by conference participants clustered into distinct groups based on location, though much more so when an unweighted distance metric was used, suggesting sharing of low-abundance microbial taxa between individuals inhabiting the same space. CONCLUSIONS: Correlations between microbial community sources and sinks allow for inference of the interactions between humans and their environment. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40168-015-0082-9) contains supplementary material, which is available to authorized users
Triplet exciton diffusion and phosphorescence quenching in Iridium(III)-Centered dendrimers
A study of triplet-triplet exciton annihilation and nonradiative decay in films of iridium(III)-centered phosphorescent dendrimers is reported. The average separation of the chromophore was tuned by the molecular structure and also by blending with a host material. It was found that triplet exciton hopping is controlled by electron exchange interactions and can be over 600 times faster than phosphorescence quenching. Nonradiative decay occurs by weak dipole-dipole interactions and is independent of exciton diffusion, except in very thin films
- …